3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $false = "a"; $v = true; echo (string) ${!$v}, PHP_EOL; echo !isset(${!$v});
based on Y2rSC
Output for 5.0.4 - 7.3.1
Notice: Undefined variable: in /in/8j971 on line 5 1
Output for 4.3.10 - 4.4.9, 5.0.2 - 5.0.3
Notice: Undefined variable: in /in/8j971 on line 5 1
Output for 4.3.0 - 4.3.9, 5.0.0 - 5.0.1
Notice: Undefined variable: in /in/8j971 on line 5 Notice: Use of undefined constant PHP_EOL - assumed 'PHP_EOL' in /in/8j971 on line 5 PHP_EOL1